I have a dimmer (Richmond/Zano GRID500) that, when turned up to full brightness, dims the lights on and off at a rate of about 1 Hz.

Turning the brightness down just a bit makes the blinking stop.

The switch did this with 6x 50W halogen bulbs, and is continuing to do this with 6x 5W LED bulbs.

Since the blinking looks deliberate, I am wondering if the switch is trying to tell me something? I found some manufacturer's literature, but there's nothing relevant there.

Any ideas?

  • Am I to understand you changed voltages? Or are you giving us the max voltage rating of the bulbs and typo'd 12 for 120? It's common enough for 120V-friendly LEDs to work on a variety of voltages, that way the same bulb can be used anywhere from Japan to the UK... Sep 30, 2018 at 0:38
  • 1
    Sorry, should have been clearer: the dimmer is, and has been, switching mains voltage (240V). The old halogen bulbs each had a 12V transformer next to them; the new LED setup is powered directly from the mains. Both configurations are pretty common here in the UK; and both exhibit the symptoms I'm describing.
    – NPE
    Sep 30, 2018 at 6:22

1 Answer 1


I managed to speak to the manufacturer, their advice was "the dimmer is faulty; have it replaced."

  • I’m having what sounds like the exact same problem: a new dimmer switch, 12 V transformer, and then at certain settings on the dimmer switch it - presumably the transformer - starts flashing the lights as if it’s trying to communicate something… I’m curious, did replacing the dimmer switch fix it for you? Thanks!
    – Ian Dundas
    Sep 28, 2021 at 19:58

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